How can I add a dollar sign in the input fields?

3. Add $ in fields indicated

Thank you!

Roger

Is this just for the form view or you want the sign to also appear in the email? You are using a number field, it's not possible to put an alpha character there. You have the dollar sign in the sub-label so I think that explains the value. 

If you really want to have it, you need to change it by a textbox field and add it as a default value: